I hadn't come across Popula before, but a glance at it doesn't lead me to think the proverbial grandma is its assumed audience. FWIW, I much prefer paper books

I hadn't come across Popula before, but a glance at it doesn't lead me to think the proverbial grandma is its assumed audience. FWIW, I much prefer paper books for many reasons (aesthetics, tactility, lack of temptations towards distraction, etc). But longevity isn't amongst those reasons - with backups etc I'm much more confident of hanging on to my epubs than I am my physical books.